50 free Respiratory System trivia questions with answers — science & nature quiz, new questions added Aug 2026.
This respiratory system trivia quiz follows a breath from the nose to the bloodstream. It starts with the parts every biology class covers: the pharynx and its three sections, the larynx and its nine cartilages, the leaf-shaped epiglottis, the windpipe with its C-shaped rings, the two main bronchi and the lobes of the lungs. Then it goes smaller, into the alveoli, the type II cells that make surfactant, and the hemoglobin that carries oxygen away. The easy questions ask how many lobes each lung has and which muscle does most of the breathing. The harder ones ask which nerve roots supply the diaphragm, how many rings of cartilage the trachea has, why aspirated food tends to land in the right lung, what 'asthma' meant in Greek, and who identified the tuberculosis bacillus in 1882. There is a round on breathing itself: tidal volume, dead space, what inhaled air is made of and why hiccups happen. If you want the rest of the body, our human body, circulatory system and digestive system quizzes carry on from here. Every answer was checked against the encyclopaedia entry for the organ, disease or person before publishing, and the sentence that supports it is stored with each question.
30 of 50 questions with answers and explanations. Play the quiz
Q 01How many lobes does the right human lung have?
Three
The left lung has only two lobes, because it gives up room to the heart and has a cardiac notch instead of a middle lobe.
Q 02Which muscle is described as the most important muscle of respiration?
The diaphragm
When it contracts the chest cavity gets bigger, pressure drops, and air is pulled in; relaxing it pushes the air back out.
Q 03What is the common name for the trachea?
The windpipe
It links the larynx to the bronchi and is found in almost every land vertebrate with lungs.
Q 04Roughly how many rings of hyaline cartilage surround the adult trachea?
16 to 20
The rings are incomplete and C-shaped, with the open side at the back so the oesophagus behind it can bulge when you swallow.
Q 05What shape are the cartilage hoops of the trachea?
Incomplete and C-shaped
Complete O rings do occur as a rare abnormality and can narrow the airway enough to cause breathing trouble.
Q 06Where does the trachea end by splitting into the two main bronchi?
At the carina
The split sits at about the level of the fourth thoracic vertebra, though it shifts a little as you breathe.
Q 07Which main bronchus is wider, shorter and more vertical?
The right
That geometry is why inhaled food or small objects tend to end up in the right lung.
Q 08If a foreign body is inhaled, where does it usually lodge?
Right main bronchus
The left bronchus leaves the windpipe at a sharper angle, so gravity and airflow favour the right side.
Q 09Approximately how many alveoli does a typical pair of human lungs contain?
About 480 million
Together they give a gas-exchange surface of roughly 70 to 80 square metres, packed into a chest.
Q 10The word 'alveolus' comes from Latin meaning what?
Little cavity
The same root gives dentists their 'alveolar' bone, the sockets that hold teeth.
Q 11Which alveolar cells release pulmonary surfactant?
Type II
They are small and cube-shaped, and can also multiply to replace damaged type I cells after injury.
Q 12What does pulmonary surfactant do to the fluid lining the alveoli?
Reduces its surface tension
With less surface tension the lung inflates far more easily, which cuts the work of every breath.
Q 13Insufficient surfactant in preterm babies causes which condition?
Infant respiratory distress syndrome
Adequate surfactant is not made until around 35 weeks of gestation, which is why very early babies struggle to breathe.
Q 21Which nerve, formed from roots C3 to C5, supplies the main breathing muscle?
The phrenic
Medical students remember the roots with the rhyme 'C3, 4, 5 keeps you alive'.
Q 22During inhalation, which way does the main breathing muscle move as it contracts?
Downward toward the abdomen
Moving down enlarges the thoracic cavity and drops the pressure inside it, so air flows into the lungs.
Q 23A hiatus hernia is when part of the stomach pushes through which structure?
The diaphragm
The stomach or lower oesophagus slips up into the thorax, which is why the condition is linked to acid reflux.
Q 14What is the larynx commonly called?
The voice box
It sits at the top of the neck and does three jobs: breathing, making sound and keeping food out of the windpipe.
Q 15How many cartilages make up the skeleton of the human larynx?
Nine
Three are single (epiglottic, thyroid, cricoid) and three come in pairs (arytenoid, corniculate, cuneiform).
Q 16Which laryngeal cartilage forms the Adam's apple?
Thyroid
Anatomists call the bump the laryngeal prominence; it is the only laryngeal cartilage found exclusively in mammals.
Q 17Which leaf-shaped flap stops food and water entering the trachea?
The epiglottis
When you swallow, the tongue levers it down over the glottis so the mouthful slides into the oesophagus instead.
Q 18Into how many sections is the human pharynx conventionally divided?
Three
They are the nasopharynx behind the nose, the oropharynx behind the mouth and the laryngopharynx that leads on to the oesophagus.
Q 19The adenoids, found in the nasopharynx, are also known as what?
The pharyngeal tonsils
They are lumps of lymphoid tissue on the back wall of the nasopharynx and form part of Waldeyer's tonsillar ring.
Q 20Which passage links the middle ear to the nasopharynx?
The auditory tube
That link is why your ears pop when you swallow or yawn on a plane: it lets the middle ear equalise pressure.
Q 24What is a hiccup, physiologically?
An involuntary contraction of the diaphragm
The glottis snaps shut about 35 milliseconds after the spasm, and that closure makes the 'hic'.
Q 25For how many years did record-holder Charles Osborne have hiccups?
68
They began in 1922 and stopped in 1990, an estimated 430 million hiccups in all.
Q 26What is the scientific name for a hiccup?
Singultus
It comes from the Latin for 'sob'; sternutation is a sneeze and tussis is a cough.
Q 27What is the formal term for a sneeze?
Sternutation
A sneeze blasts air out through the nose and mouth, usually because something is irritating the lining of the nose.
Q 28Sneezing triggered by sudden bright light is called what?
Photic sneeze reflex
It is sometimes nicknamed ACHOO syndrome, and it runs in families.
Q 29What is the potential space between the two pleurae around each lung called?
The pleural cavity
It holds a thin film of serous fluid that lets the lung slide against the chest wall with each breath.
Q 30Which pleura covers the surface of the lung itself?
Visceral
The parietal pleura is the outer layer lining the chest wall; only a film of fluid separates the two.